Underwater electrical cables and marine conductors in general cause major problems when they begin to leak. Leakage of course is common due to the fact that such cables, and their connectors, commonly operate in subsurface environments or in near surface atmospheric environments characterized by extreme salt and humidity. The primary water and humidity sealing means in underwater connectors is generally the insulation encapsulating the strands of individual conductors, or it is an encapsulating plastic around the machined stainless steel connector. Frequently, these connectors are made of corrosion resistant metals, such as stainless, or the like, and are coated with a plastic coating for the purpose of precluding entry of moisture.
Further, in marina seismic operations, underwater electrical plugs or connectors are needed to connect power and instrumentation conductors to other equipment, such as seismic sound generators, i.e., air guns. These "guns" are used as a sound source to obtain acoustic reflections from the sea-floor. Typically, they are fired every ten to fifteen seconds producing extremely strong pressure waves. As a result, the electrical cables, conductors and connectors are subjected to a great deal of structural abuse, and normally they may not last for extended periods of time before developing leaks or other operational defects. Typically, these components, such as electrical connectors, are exposed to such blasting forces and also to the extremely adverse nature of the environment, and will not last long if they are not able to withstand the conditions. Therefore, all of the electrical connectors and other components used in these harshest of environments must necessarily withstand repeated explosive forces on their exteriors while allowing for a degree of flexibility therewithin lest the internal conductor be jolted loose from its external housing. This is best accomplished by having a rigid or very strong external housing material which will not fracture while simultaneously precluding leakage from without. Also, however the electrical conductor inside the housing must be mounted within a flexible shock absorbent material in order that repeated percussive forces do not produce a short in the circuit. Applicant is unaware of the fact that conductors may have relatively hard external housings. The conductors do not have flexible shock absorbent interiors. Moreover, the exterior and interior are commonly of different materials, such as for example metal and rubber, thus necessitating a difficult and expensive bonding technique which frequently results in an unreliable adhesion. This is believed to be true whenever different materials of substantially different hardness and/or density are bonded together. Applicant is unaware of a marina electrical connector having a relatively hard external housing and a relatively soft internal, flexible core capable of absorbing sudden shock and adverse external conditions and in which the two materials are substantially the same so as to facilitate reliable long term bonding there between.
Accordingly, it is a primary purpose of the invention disclosed hereinafter to provide an electrical connector which solve the problems described above and which can be utilized in marine seismic operations. Another purpose of the present invention is to improve the shock absorbing capabilities of electrical connectors through the use of a flexible internal core that enhances absorption of shock and hence minimizes electrical circuit disturbance, and which further is characterized by a relatively hard external housing to protect the flexible internal core against physical damage from sudden impacts of usage.
Another significant feature and advantage of the present invention is to provide a marine connector which markedly reduces the substantial costs associated with current steel, or other metal, electrical connectors. These electrical connectors, commonly used today, are characterized by a plurality of component parts, each of which must be machined in a series of close tolerance machining operations. These operations are extremely costly and are essentially eliminated by the invention herein.
Accordingly, it is another principal object of this invention to provide an electrical connector which, despite its necessary usage in the marine industry is not made of stainless steel or any other metal alloy normally resistant to corrosion and other abusive environmental conditions. Instead, applicant has discovered a method for making reliable multi-component electrical connectors which, heretofore, were not capable of reliable permanent fusion to one another. The dual material electrical connector of the invention is characterized by a flexible shock absorbent internal core and relatively hard external housing, each fusingly connected to one another in an irrevocable bond. Heretofore, the state of the art has not, to applicant's knowledge shown an ability to produce a flexible internal core surrounding the conductors which could be reliably bonded to the external housing.
Applicant has discovered the use of a glass impregnated external housing consisting of a hard plastic material and an interior shock absorbent flexible material of substantially the same plastic which obviates the short comings of the prior art and which not only enables the production of electrical connectors capable of operational advantages over that which has been known heretofore but which are markedly simpler to make and less expensive. These operational advantages and consequent cost saving techniques described herein are accomplished in a connector which can be manufactured from plastics, instead of metal which must be machined in a series of expensive and time consuming operations. The external plastic and internal plastic, though of different hardnesses, are irrevocable bonded or fused to one another because of their same molecular structure. As a consequence, the electrical connector of the invention can be marketed at a significant savings in price over that which is present in the current marketplace. The above advantages, and numerous other features and advantages of the invention, will become more readily apparent upon a careful reading of the following detailed description, claims and drawings, wherein like numerals denote like parts in the several views, and wherein: